220-1101 Question 247
Single answerSerial Attached SCSI [Small Computer System Interface] (SAS)A technician is upgrading a small business file server that currently uses several SATA hard drives. The new server motherboard includes a SAS controller, and the company wants better reliability while reusing as many existing drives as possible. Which statement best describes the technician's options when connecting drives to the SAS controller?
- A
The technician can connect SATA drives to the SAS controller, but cannot connect SAS drives to a SATA-only controller.
- B
The technician can connect either SAS or SATA drives to any SATA controller because SAS is backward compatible with SATA.
- C
The technician must use only SAS drives with the SAS controller because SATA and SAS use completely different signaling and are not interoperable.
- D
The technician can connect SAS drives to SATA ports if a passive adapter cable is used.
Show answer and explanation
Correct answer: A
Explanation
In a real A+ Core 1 scenario, the important applied knowledge is understanding compatibility when upgrading or servicing storage in workstations and servers. SAS is commonly used in enterprise environments because it supports features such as dual-porting, higher reliability expectations, and controller support for both SAS and SATA devices. A SAS controller can typically communicate with SATA drives, which is useful when reusing existing disks during a server refresh. However, SATA controllers do not support SAS drives because SAS requires different controller logic and protocol support. This distinction is consistent with vendor documentation from enterprise storage manufacturers and standard deployment guidance for SAS host bus adapters, RAID controllers, and server backplanes.
- A. Correct.
Correct. A key practical advantage of SAS is controller-side compatibility with SATA drives. In many business servers, a SAS controller or backplane can address either SAS or SATA disks, which helps organizations reuse existing SATA drives during upgrades. However, the reverse is not true: SAS drives require a SAS controller and cannot operate from a standard SATA-only controller.
- B. Incorrect.
Incorrect. This reverses the actual compatibility relationship. A SAS controller can typically work with SATA drives, but a SATA controller cannot communicate with SAS drives. Someone might choose this option by assuming 'backward compatible' works both ways, but SAS support depends on the controller and protocol handling.
- C. Incorrect.
Incorrect. SATA and SAS are different technologies, but they are not completely isolated in practice. SAS controllers are specifically designed to support SATA drives in many deployment scenarios. This option reflects a common misconception that different enterprise and consumer storage standards cannot be mixed at the controller level.
- D. Incorrect.
Incorrect. A passive adapter cable does not add the protocol support needed for a SATA controller to operate a SAS drive. SAS drives need a SAS controller or SAS-capable backplane. This distractor is plausible because adapters exist for many physical connector changes, but protocol compatibility cannot be solved by a simple passive cable.